Will "Uptown Funk!" (RCA) be the longest-running No. 1 hit of all time?

It could be. The Mark Ronson hit featuring Bruno Mars has already racked up 14 weeks on top this year, making it the longest-running No. 1 of this decade, and it is now three weeks away from dethroning Mariah Carey and Boyz II Men's ballad "One Sweet Day," which set the record with 16 weeks at No. 1 in 1995-96.

"Uptown Funk" has already repelled a charge from Ed Sheeran's "Thinking Out Loud," which spent eight weeks at No. 2 waiting for a crack in the "Funk" foundation that never came. But to break the record, "Funk" has to face down Maroon 5's sweet love song "Sugar" and Wiz Khalifa's rapidly climbing "See You Again" from the movie blockbuster "Furious 7" for a few weeks.

That's a tall order, but as Mars would say, "Don't believe me, just watch." And it's hard to count "Uptown Funk" out of anything, considering its unusual run.

"It's definitely one of the best things I've ever done," Ronson told Billboard. "And I know that it's one of Bruno's favorite things that he's ever done, as well."

So far, the song has sold more than 5 million copies. It's been covered countless times on YouTube, by everyone from grade school classes to senior citizen groups. First lady Michelle Obama used it as the theme for the fifth anniversary of her "Let's Move!" exercise campaign and danced to it during the White House Easter egg roll and a recent appearance on Ellen DeGeneres' show.

It has introduced new generations to the funk of James Brown and the Minneapolis sound of the '80s engineered by Prince. Plenty of teens have now heard The Time's "Jungle Love" and Sheila E.'s "The Glamorous Life" as oldsters reminisce about the song's roots.

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However, the secret to long-running success of "Funk" may be in Ronson's background as a DJ. While most big hits feature one hook and return to it over and over (think "Here's my number, so call me maybe"), "Funk" lands one hook after another, grafting them onto the main chorus the way a DJ might built a set.

That helps with the song's longevity. Normally, a hit this big burns itself out after a few weeks because people grow tired of the hook that they initially loved. However, in the case of "Uptown Funk," when you're tired of being too hot and calling the police and the firemen, you can move on to the James Brown-like chant of "Uptown funk you up," and after that the naughty couplets of "if you sexy, then flaunt it" and "if you freaky, then own it."

Noted Canadian musicologist Chilly Gonzales told the BBC that he is a big fan of the song, calling it an elegant, modern pop song, adding that the climax of the song was influenced by techno music. "We have a mix of the old, the new, the modern and the classic -- and that's why I love 'Uptown Funk.' " he said.

All those nuances show that the seven months of work that went into the song have really paid off.

"Uptown Funk" started off as a musical idea that Mars and his band would kick around during sound checks of his "Moonshine Jungle" tour in 2014. Ronson and co-producer Jeff Bhasker began following Mars around on tour to work on the song and record bits of it.

"I pushed myself much more than I have on anything else in the past," Ronson told Billboard, adding that at one point in the process he collapsed from the stress. "There was all of this pressure because Bhasker was leaving at the end of the day. The plan was for me to record my guitar part by lunch. Lunchtime comes around and I still haven't nailed the part. We go out and in the stress of finishing this song I fainted in the restaurant. I threw up three times. Jeff had to carry me back to the studio."

The strain has been worth it, though. "Funk" has established Ronson -- previously best known as a producer on Amy Winehouse's "Back to Black" album and on Mars' "Locked Out of Heaven" -- as a performer in his own right. His album "Uptown Special" reached the Top 5 and he has begun the push for the follow-up single to "Uptown Funk," the grittier funk number "Feel Right" featuring Mystikal. There are plenty more potential hits on the album, including some co-written with Pulitzer Prize-winning novelist Michael Chabon.

Ronson says he is thrilled, though, if he is forever associated with "Uptown Funk." "You always hear people complaining that they weren't into their biggest hit," he told Rolling Stone. "I feel pretty lucky that the song that is my biggest hit is something that I am as proud of, and that it's also something I did with a friend."

LONGEST CHART REIGNS

Though shifts in chart methodology and the tightening of radio playlists make it easier for songs to have longer runs at No. 1, it's been a while since any smash has come within striking distance of the title, held by Greenlawn native Mariah Carey and Boyz II Men for nearly 20 years. Here's a look at the Top 10 all-time longest runs at the top, according to Billboard: